In recent years, liquid crystal displays (LCDs), and other flat panel display devices, have become increasingly popular as mechanisms for displaying information to operators of vehicles, such as aircraft. One of the reasons for this is that LCDs are capable of providing very bright and clear images that are easily seen by the user, even in high ambient light situations, such as daytime flight.
Conventional active matrix (AM) LCDs use spatial averaging of the pixels to generate full color from three different colors (e.g., red, green, and blue (RGB)) of light emitters, such as light emitting diodes (LEDs), along with an array of color filters. However, approximately two-thirds of the available backlight power is often absorbed by a color filter array which significantly impairs power efficiency. This loss of power efficiency leads to thermal management being a significant issue in conventional LCD displays for applications requiring high display luminance.
Recently, field sequential color (FSC) displays have been developed for use with various image sources, such as LCDs, cathode ray tubes (CRTs), liquid crystal on silicon (LCOS), and digital micro-mirrors (DMMs). FSC displays do not use color filters and yet generate full color by sequentially writing each pixel in the display in conjunction with sequentially switching RGB emitters in the backlight. Full color is generated at each pixel by temporally averaging the RGB emissions of each pixel. Because color filters are not required, the power consumption is greatly reduced, which often eliminates the need for active cooling of the display in high luminance applications. Additionally, display resolution is effectively tripled when compared with conventional LCDs, as full color may be generated at each individual pixel, rather than using multiple pixels in combination.
However, there still are several limitations to FSC displays, such as FSC LCDs, with respect to maximizing luminance and a propensity for color breakup that adversely affects image quality. In a conventional FSC LCD, each video frame is subdivided into three equal sub-frames, each for refreshing the display with one of the RGB data. Thus, a 60 Hertz (Hz) video refresh rate used in a conventional RGB pixel LCD leads to a 180 Hz refresh rate for an FSC LCD. The RGB LED backlight operation is synchronized with writing the RGB data for the FSC LCD and, in order to avoid unintentional color mixing from one sub-frame to the next, the duty cycle of the RGB emitters has to be reduced to much less than the sub-frame period. The RGB emitters are turned “on” only after all the rows in the display are addressed and the pixels have switched to the demanded state, which reduces the duty cycle of the LED emitters to as low as, for example, 20% of the sub-frame time. This in turn reduces the maximum achievable display luminance using a given RGB backlight. Furthermore, to reduce color breakup in FSC LCDs, the refresh rate is often increased to, for example, 240 Hz, further restricting the duty cycles of the RGB emitters in the backlight, and thus the maximum achievable display luminance.
Accordingly, it is desirable to provide a method and system for improving performance in a FSC display device, such as increasing display luminance and power efficiency and decreasing color breakup. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.